Identify the element
Locate the element on the periodic table
Use the periodic table trend to estimate ionization energy
Read the first ionization energy value from a data table or database
For successive ionization energies, use tabulated values for the specific element
Use the electron configuration to determine which electron is removed first
Apply the ionization energy equation if energy and wavelength are given
Use (E = hnu)
Use (E = frac{hc}{lambda})
Convert the result to the required units, usually kJ/mol